Sunday, December 16, 2007

For most of a week, I've been following the story about the acceleration of human evolution, talked about here and almost everywhere else on the web. The basic point of a paper coming in PNAS is that the rate of human evolution has picked up dramatically over the last handful of millennia. This has to do with the rise of farming, increased population size, etc. The paper tackles the (to me always troubling) notion that we've stopped evolving and turns it on its head. But please don't take this one-liner summary if you haven't followed the story … read about it. The best scoop looks to me like John Hawks's blog. He's one of the authors and has already posted good comments on the acceleranistas (his term) and critiques of the piece, and promises more.

I'm trying to follow the stuff on genetics and the math used, but can't comment on those things directly. Still, I immediately wondered if this wasn't testable: Not everybody did switch to farming and saw increased population size, etc. and you should be able to contrast the presence of new alleles by that variable. (Lawrence Moran raises what I take to be the same basic point here.) Hawks (who teaches Anthro here) was quoted in one of our student papers as saying this:

We are more different genetically from people living 5,000 years ago than they were different from Neanderthals.

This isn't just a claim about disease resistance and such, but basic cognition, it sounds like. If so, whether or not we assume Neaderthals had language (see here), language would have been structurally different from what we see today. That hunch is supported by another collaborator on the project, Eric Wang, who was quoted as saying this:

Instead of saying, ‘Go straight, kill a deer, eat it,’ people have to free up their mind and be able to articulate ideas that were otherwise abstract. … It’s a different layer of selection.*

I pondered language-related angles of this for a while, but didn't get any inspiration until yesterday, when a colleague emailed with a question:

Just an aside, when was the Rigveda written and do we think that Panini's brain was different than ours? … This raises a very important question: can humans' genetics be so different (statistically speaking) in so short a time that our brains are fundamentally different than Panini's? … It seems to raise all kinds of issues about the purpose of studying 'dead' languages or saving endangered languages. Once they're gone, we can't use them as evidence for linguistic theory, just as historical relics of past cognitive function.

OK, let's say Panini — author of a brilliant grammar of Sanskrit and the envy of many linguists — lived upwards of 2,500 years ago, and that the Rig Veda was composed more like 3,500 before the present. Presumably his brain would have been a little different, and the authors of the Rig Veda probably more so. In dating Indo-European, people talk about reaching a good 5,000 years back (a date also the above quote). The claim would seem to be that IE was spoken by people with different cognitive capacity than we have today. Of course, lots of linguistic prehistory deals with dates a lot farther back.

Under this view, wouldn't early IE be structurally different from modern languages in some ways due to cognitive differences? If these guys are right, comparative and historical linguistics becomes a completely new game: By the time depth of IE, you'd have to assume language was spoken by people who were evolutionarily pretty different from us. For Nostratic and all other proposals by "long rangers", you'd have to presume dramatic differences. One way to really rile up old-school historical linguists is to claim that languages were 'simpler' in such times.

I'm really curious how this will play out.

* If this is right and it stems from what they think it does, it raises big questions about emerging differences between people who've been far less or more isolated during that time. That makes me really nervous, but I don't know what story these folks have on that and maybe it ends up less scary.

3 comments:

harpend
said...

Did you ever look at Julian Jaynes' "The Origin of Consciousness in the Breakdown of the Bicameral Mind?" This book had its ten minutes of fame in the 1970s I think, and reviewers did not overtly mock it.

He says something like humans became fully conscious in the time of the Greeks in antiquity.

Thanks much ... I haven't thought about that book in years! I read it probably in 1978 (must have been fairly new at the time) and don't recall the reviews, but do remember skeptical but hardly mocking conversations about what that view meant for prehistory.

You weren't implying it, but just to be really, really clear to readers in general: I wasn't mocking anything about this new work, and I'm sure the colleague in question wasn't either.

When bold hypotheses come in from other fields, we of course start thinking about what they mean for our own fields.